Control system



w. A. DERR CONTROL 'SYSTEM July 20, 1948.

Filed Dec. 4 27, 1944 INVENTOR b BQ@ RQU Patented July 20, A1948 UNITEDSTATES PATENT OFFICE CONTROL SYSTEM Willard A. Derr, Wlkinsburg, Pa.,assgnor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a;corporation of Pennsylvania Application December 27, 1944, Serial No.569,998

3 Claims; 1

My invention relates', generally, to control systems, and it has.reference in particular to supervisory control systems;

Generally stated", it is an object :if my invention to provide asupervisory control system having a telemetering' point, and which issimple and inexpensive to manufacture` and is efficientV in operation.

-More specifically it is an' object of my invention to provide forautomatically obtaining, at' periodic intervals, an indication of theintegrated reading and demand' of an electrical quantityA at a remotestation' over a supervisory control system with a minimum ofinterference with. other supervisory and control operations.

It is also an [object of my invention' to provideV for storingelectrical impulsesv at a remotev station of' a supervisory controlsystem and releasing them at periodic intervals i-norder to obtain anindication at a dispatch-ing oiiic'e of the integrated reading of'kilowatt hours and also of the kilowatt demand during predeterminedintervals;

Another object of my inventionV is to' provid-e at periodic intervalsfor reproducing' telemeteringv impulses oi'electricalenergy at a remotestation ina supervisory control system, at a rate much greater tl'ianvthe origin-al?v rate, andtransmitting them over a supervisory Vcontrolchannel in relatively short ifnterval'sf in response to timed signals'from. a dispatching ofi-loe.

Yet another object of my invention is to provide for automaticallyobtainingl telemetering` indications over' a supervisory con-trol systemduring' relatively' short spaced' apart operating intervals; unlessvsome other supervisory function is being' performed.

Still another object of my invention is toprovide for storingtelemeterifng impulses whichY are Other* objectsw-ill partV be obviousand will in part be explained hereinafter.

l In` practicing my invention, an impulse storage device is used tostore telerneteringV impulses at a remote stationand release themperiodical- 1y atafrate which: is= greatly inexcess of the storage.rate.: Transf-ermeans are usedl tei-periodicalllydisconnectthesupervisory channel: from the supervisorycontrol equipmentA andconnect/lit totelemetering means for transmitting and receiving theimpulses. Timing means at the dispatching cnice periodi-cally selects atelemetering point on the supervisory control system for eife'ctngj thisoperation, and upon the cessation of teleme-l tering impulses, thesupervisory control equipment is reset so as to be available for anyother supervisory control' operations until the initiation of the nextmetering interval.

For a more complete understanding off the nature and scope of myinvention reference may be made to the followingv detailed description,which may be studied in connection lwith the aocompanying drawing, inwhich the single figure is a diagrammatic' View of a supervisorycontrol'` system embodying the invention in. one of. its formsl Thesingle iigure ofthe drawing` is a diagrammatic view of asup'ervisorycontrol system where'- in the reference numeral t0' maydenote,` generally, the dispatching office equlpmenn and the referencenumeral l-l may denote, generally, equipment at a remote station whichmay he con"- nected with the dispatching office by a single suipervisorycontrol channel represented by the conductors I3 and Ill.

The' reference numeral l5" may denote-, gener;- ally, supervisorycontrol equipment at the dispatching onine, whichV may include a portionthereof` represented"V by the enclosure` i8. The Supervisory controlequipment l5 may be similar in'` generali to'A that shown andi describedin the Bos*- waul Patent'2,091,30 1, which issued on August' 31', 1937,and the enclosure I-B relinesents,v generally, a principal portionl ofthe disp'atching,V cnice'. equipment which is identical witlithat shownand described indetail in the Boswau patent'. Equipment of the Boswaupatent whichliasbeen changed in any respect is shown to they immediateright ofthe boxed' enclosure; All parts'v of the equipment shown in theBoswau" patent are designated by the same numerals as in' the Bos'- waupatent, and' any additions" or al'teratio'rs` ae designated bynumera'lsnot appearing'` in thetBoswao: patent so' as todistinguish themtherefrom; The circuits of the line relay' 2110 and" the im'- pulsingyrela-yI 201' have been alteredv to provide for parallelT circuitoperation in a manner which is well known in the art, in order to`permit; metering over thesupervisory channel.

'In a; like" manner; the numerall f8* may' des'ig'- nate, generally,supervisory' control equipment a't, the remote statiom which' includesa. principali portion thereof represented', byY the enclosure |592.which is identical in' every respect with a principal portion of theremote station equipment shown and described in connection with theabove mentioned Boswau patent. The equipment or" the Boswau patent towhich changes have been made is shown outside and immediately to theleft of the enclosure. Equipment appearing in the Boswau patent isdesignated by the same numerals as used therein, whereas additionalequipment is designated by different numerals not appearing in theBoswau patent. The circuits of the line relay 40|! and the impulsingrelay 40| have also been changed to provide for parallel circuitoperation in order to permit metering over the channel. K

In order to provide for obtaining indications at the dispatching officeof the kilowatt *demandV at the remote station, as well as an integratedreadingpof the kilowatt hours, without tying up the supervisory controlequipment for any longer than necessary, telemetering means such as thekilowatt hour demand meter may be provided atthel dispatching cnice foroperation in conjunction with telemetering means such as the impulsestorage device v2| at the remote station, which provides for storingimpulses of electrical energy produced by a watthour meter 22 at theremote station during relatively long intervals and transmitting them ata rate much greater than the original rate over the supervisory channelat periodic intervals. 'The meter 2U may be operated in a well knownmanner by an impulse relay 23, responsive to impulses transmitted by thedevice 2 I.

The energy storage device 2| may be of substantially the same type asshown in Patent No. 2,286,180, which issued in June 9, 1942, to G.W.'Pickel`s,` and is assigned to the assignee of the present invention.It may, for example, comprise impulsing means such as `the commutatordevice 24 which is disposed to be driven by the watthour meter 22 forproducing impulses of electrical energy from a source such as thebattery 25, at a rate which is dependent upon the rate of flow ofelectrical energy in the circuit which is being metered lby the watthourmeter 22. In order to provide for transmitting over the supervisorychannel a corresponding number o-f'impulses for operating the demandmeter 2D at the` dispatching oiice, without constantly tying.. up thesupervisory channel, means may be provided for storing the impulsesproduced by the. commutator device 24 during relatively long periods andtransmitting them at a rate greater in excess of the rate of storageduring relatively short periods by means of a commutator device 21 whichmay lbe oper-ated by a motor 28 for periodically shunting a controlresistor 26 `to vary thecurrent in the supervisory channel.

y Operation of the motor 28 may be controlled by means of a contactdevice 29 which comprises a rotatable disk 30 having a pin 3|projectin'g therefrom for urging a movable contact 29a away from astationary contact 29h, which contact members are connected in theoperating circuit of the motor 28. Operation of the disk 3|l'may becontrolled by a differential device 32 having planetaryV gears y33 foroperatively connecting a pair of sun gears 34 and 35 which may beactuated by means of solenoid operated ratchet devices 36 and'31 havingoperating Windings `38 and Saconnected incircuitrelation with .thecommutator devices 24.7and 21, respectively. TheV ratchet devices'36 and31 maybe so arranged that the disk 30 is .permitted to rotate so as topermit engagement of the contacts 29a and 29h the commutator device 21.15`

4 so long as there is a positive differential between the number ofimpulses produced by the commutator device 24 over the numbertransmitted by the commutator device 21.

In order to provide for transmitting telemetering impulses over thesupervisory control channel without interfering with the operation ofthe supervisory control equipment, transfer means such as the transferrelays 40 and 4| may be provided at the remote station for disconnectingthe supervisory control conductors I3 and I4 from the supervisorycontrol equipment and connecting them to the telemetering meansincluding O-peration of the transfer relays 4|)A and 4| may fbe effectedby means of control relays 42 and 43. The control relays may be of thedelayed dropout type and may be arranged to produce a timed impulse atthe end of the point selection check code, when the supervisory controlrelay 403 releases, for energizing the transfer relay 4|.

At Ithe dispatching ofce, similar transfer relays 46 and 41 may beprovided for disconnecting the supervisory control channel from thesupervisory control equipment and connecting it for telemetering. Thetransfer relay 41 may be of a delayed drop-'out type in order to providea slight time delay between the disconnection of the supervisory controlchannel from the metering circuits and the restoration thereof .to thesupervisory control equipment. Y

In order tol provide for automatically determining the demand at theremote station and the integrated reading of the watthour meter 22 atperiodic intervals, Vmeans such as the timeclock 49 may be provided forperiodically eiiecting operation of the supervisory control lequipmentat the dispatching oflce to connect the supervisory control channel tothe telemetering equipment. Means such as the control relay 50 may beprovided for initiating the selection of a telemetering point inresponse to an impulse from the time-clock 49. In order to prevent anyattempt to set up a telemetering circuit when the supervisory controlequipment is performing some other operation, and to provide forreturning the supervisory equipment to normal after a metering operationmeans such as the auxiliary or reset relay 52 may be provided, whichoper- 4ates under the control of the control relay 50 through ianenergizing circuit controlled by the supervisory con-trol sending startrelay 2|8 and other of the supervisory control relays of the Boswaupatent which operate selectively during supervisory and control sendingand receiving operations. y

With a view to determining resetting the supervisory control equipment,as Well as disconnecting the supervisory control channel from themeteringequipcrnent, -a pair of auxiliary control relays 54 and 55 maybe provided which maintain the reset relay 52 energized so long astelemetering impulses are received from the remote station. At thetermination of impulses from the remote station, the auxiliary controlrelays operate to deenergize the reset relay and permit resetting of thesupervisory control equipment in much the usual manner.

In operation, the time-clock 49 produces impulses at predetermined timeintervals for which the demand is desired, for example, at 15 minuteintervals. Upon-theoccurrence of an impulse, the [control relay 50 isenergized through a circuit extending from the negative terminal through.the operating winding armature 54a and and the auxiliary control relay55 drops out upon the termination of the impulses, interrupting theenergizing circuit for the control relay 54 at armature 55a. Thisinterrupts the holding circuit for the reset relay 52 at armature 5419.vThe relay 52 deenerglz'es and picks up the supervisory control resetrelay 2|4 through armature 52d'and back contact. Relay 2|4 operates,interrupting the holding circuit of the transfer relay 46 at armature2|4b. Transfer relay 46 is deenergized and disconnects the supervisorycontrol channel from the telemetering circuit at armature 46a. Thisinterrupts the line circuit and deenergizes the transfer relay 40 at theremote station which accordingly interrupts the holding circuit for itscompanion transfer relay 4| at armature 40a. A predetermined time afterthe deenergization of transfer relay 4B, it companion `transfer relay 47drops and reconnects thesupervisory control channel to the supervisorycontrol equipment at armature 41a.

Reset of the supervisory control `equipmentvisl provided by theenergization of the line relay 20| at the Adispatching oflice, throughan operating circuit extending from negative through the operatingwinding of relay 20|, armature 244 and front contact of the reset relay2 |4, through back contact and armature 41o of the transfer relay 41.This produces the long reset pulse and the supervisory control system isthus restored to a normal Ycondition ready for any subsequentsupervisory control operation or a subsequent metering operation.

Should a supervisory-or control Yoperation be attempted while atelemetering operation is taking place over the supervisory channel, fsuch supervisory or control function willV merely be held in abeyancepending the end of the telemetering operation in a mannersimilar to thatdescribed in the Boswau patent with reference to conflicting supervisoryor control operations. Likewise, should a supervisory orv controloperation be taking place when the metering clock closes its contacts,the control relay 50 merely seals in and awaits the termination of thesupervisory or control operation whereupon the circuit for the relay 52can be completed and the stored metering impulses transmitted.

From the above description and accompanying drawing, it will be apparentthat I have provided, in a simple and eiective manner, for automaticallyeffecting periodicV indications ofthe demand and integrated reading ofan electrical quantity at a remote station. Operation of thetelemetering means over the supervisory control channel is so effectedas to utilize the channel only for a minimum of time, thus releasing itfor operation or supervisory functions during a principal portion of thetime.

Since certain changes may be made in the above-described constructionand diierent embodiments of the invention may be made Without departingfrom the spirit andscope thereof, it is intended that all the mattercontained in the above description and shown in the accompanying drawingshall be considered as illustrative, and not in a limiting sense.

I claim as my invention:

1. In a supervisory control system having a dis.

tionalmpulse telemetering means at a metering point at a remote stationincluding means for producing electrical impulses at a rate proportionalto a quantity to be measured and means for storing said impulses andproducing an equivalent number of impulses at a much faster rate, demandindicating means at the dispatching oilice including an impulse operateddemand meter having ka predetermined demand interval, transfer meansattheremote station and dispatching ofce operable under the control of thesupervisory equipment for transferring the channel from the supervisoryequipment to the telemetering means and the demand indicating means atthe termination of a point selection check code,fcontrol means at thedispatching office including a timeclock operable at predeterminedintervals corresponding to the demand interval to produce a timedimpulse, a control relay operablein response to said impulse to effectoperation of the supervisory equipment automatically to effect selectionof the'remote metering point and operation of the transfer means, andreset means at the dispatching office including a reset relay of( 1. thedelayed dropout type disposed to be maintained in the operated positionduring receipt of the equivalent impulses and responsive to thetermination of the equivalent pulses for rendering the transfer meansinoperative and effecting reset of the supervisory equipment.

2. In a multiple point supervisory control system for a dispatchingoiiice and a remote station-supervisory control equipment at the oiceand station operating over a single signal channel lto send and receivedifferent impulse codes for selecting any one of the multiple points forperforming one of a plurality of supervisory and' control functions,telemetering transmitting means at the remote station including meansfor storing energy impulses at a rate dependent upon a quantity to bemeasured and producing a corresponding number of impulses at a latertime at a rate greatly exceeding the storage rate, demand rateindicating means at the dispatching office including an impulse operatedmeter, transfer means at the dispatching olce responsive to thetermination of a check code in selecting the metering point to connectthe channel to the indicating means, transfer means at the remotestation including control relays of the delayed dropout type responsiveto termination of said point selection check code for connecting thechannel to the transmitting means after a time delay, control meansincluding a time device at` the dispatching office controlling theoiiice supervisory lcontrol equipment for periodically selecting ametering point to effect operation of the transfer means atpredetermined intervals of time totion, telemetering means includingmeans for' storing energy impulses at a; rate dependent upon a quantityto be measured and producing -corresponding impulses under thecontrol'of a remote metering point relay at a later time interval at arate greatly in excess of the storage rate, telemeterng means at thedispatching office including an impulse operated meter device, transfermeans normally connecting the channel to the supervisory equipmentoperable upon the selection of a metering point relay from thedispatching office to connect the channel to the telemetering means forrecording during a relatively short interval the amount of the quantityto be metered which has been measured since the preceding interval, saidmeans being operable to reconnect the channel to the supervisoryequipment a predetermined time after it is disconnected from thetelemetering means, means at the dispatching ofiice for periodicallyselective a metering point at predetermined intervals of time, and meansresponsive to the cessation of stored im- 10 pulses for rendering thetransfer means inoperative and resetting the supervisory equipment.

WILLARD A. DERR.

REFERENCES CITED The following references are of record in the iiie ofthis patent:

UNITED STATES PATENTS 10 Number Name Date 1,919,992 Stewart July 25,1933 1,942,424 Hershey Jan. 9, 1934 2,286,180 Pickels June 9, 19422,327,251 Derr Aug. 17, 1943 l5 2,329,370 Hicks Sept. 14, 1943 2,372,593McWhirter Mar. 27, 1945 2,376,752 Bostwck May 22, 1945

